Wash. Rev. Code § 41.45.090
The department shall collect and keep in convenient form such data as shall be necessary for an actuarial valuation of the assets and liabilities of the state retirement systems, and for making an actuarial investigation into the mortality, service, compensation, and other experience of the members and beneficiaries of those systems. The department and state actuary shall enter into a memorandum of understanding regarding the specific data the department will collect, when it will be collected, and how it will be maintained. The department shall notify the state actuary of any changes it makes, or intends to make, in the collection and maintenance of such data.
At least once in each six-year period, the state actuary shall conduct an actuarial experience study of the mortality, service, compensation and other experience of the members and beneficiaries of each state retirement system, and into the financial condition of each system. The results of each investigation shall be filed with the department, the office of financial management, the budget writing committees of the Washington house of representatives and senate, the select committee on pension policy, and the pension funding council. Upon the basis of such actuarial investigation the department shall adopt such tables, schedules, factors, and regulations as are deemed necessary in the light of the findings of the actuary for the proper operation of the state retirement systems.
RCW 41.45.090